Influence of the atomic diffusion mechanism on morphologies, kinetics, and the mechanisms of coarsening during phase separation

1999 ◽  
Vol 59 (21) ◽  
pp. 13681-13692 ◽  
Author(s):  
T. T. Rautiainen ◽  
A. P. Sutton
Keyword(s):  
Phase Separation ◽  
Diffusion Mechanism ◽  
Atomic Diffusion

scholarly journals Synthesis and Characterization of Zn-Nix Advanced Alloys Prepared by Mechanical Milling and Sintering at Solid-State Process

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
José G. Miranda-Hernández ◽  
Héctor Herrera-Hernández ◽  
Carlos O. González-Morán ◽  
Jesús Noé Rivera Olvera ◽  
Ivanovich Estrada-Guel ◽  
...  
Keyword(s):  
Solid State ◽  
Intermetallic Compound ◽  
Diffusion Mechanism ◽  
Morphological Structure ◽  
Atomic Diffusion ◽  
System Alloy ◽  
X Ray Diffraction ◽  
State Process ◽  
Hcp Structure

Mechanical ball milling assisted by sintering in the solid state was used in this research to produce the Zn-Nix system alloy. The derivative powder compositions of Zn-Nix (x = 0, 5, 10, 15, and 20 wt.%) were obtained to study the Ni effects on the microstructural and mechanical properties. It is worth remarking that conventional methods are not appropriate for the manufacture of the Zn-Nix system alloy. The morphological structure and phases were examined by optical microscopy, X-ray diffraction, and SEM/EDS elemental mapping, whereas the mechanical behavior was accomplished by means of a diamond indentation print (Hardness Vickers). The results showed that the intermetallic γ-ZnNi phase did not form during milling time (<4 h); it appears after the sintering process, which is associated with atomic diffusion mechanism through grain boundary at the minimum interfacial energy (ΔG256°C = −13.83 kJ·mol−1). The powder Zn-Ni10 was found to have better properties. Semispherical coarser particles were seen into the metal matrix (Zn δ-hcp structure) as segregates; however, each particle contains an intermetallic compound Zn-Ni that encloses the Ni (α-fcc structure) pure phase. The Ni-α phase was then transformed into a γ-ZnNi intermetallic compound which shifts to higher values of mechanical hardness from about 60 HV to 400 HV units.

Anisotropic atomic diffusion mechanism of N, C and H into Sm2Fe17

1995 ◽  
Vol 222 (1-2) ◽  
pp. 27-32 ◽  
Author(s):  
Chris N. Christodoulou ◽  
Norikazu Komada
Keyword(s):  
Diffusion Mechanism ◽  
Atomic Diffusion

scholarly journals Project VeSElkA: Vertical Stratification of Element Abundances in CP stars

2015 ◽  
Vol 5 (1) ◽  
pp. 3-10 ◽  
Author(s):  
V. Khalack ◽  
F. LeBlanc
Keyword(s):  
Spectral Analysis ◽  
Main Sequence ◽  
Diffusion Mechanism ◽  
Stellar Atmospheres ◽  
Vertical Stratification ◽  
Atomic Diffusion ◽  
Chemical Abundances ◽  
Element Abundances ◽  
Chemically Peculiar ◽  
New Research

A new research project on spectral analysis which aims to characterize the vertical stratification of element abundances in stellar atmospheres of chemically peculiar (CP) stars, is discussed in detail. Some results on detection of vertical abundance stratification in several slowly rotating main sequence CP stars are presented and considered as an indicator of the effectiveness of the atomic diffusion mechanism responsible for the observed peculiarities of chemical abundances. This study is carried out in the frame of Project VeSElkA (Vertical Stratification of Elements Abundance) for which 34 slowly rotating CP stars have been observed with the ESPaDOnS spectropolarimetre at CFHT.

Description of Phase Separation in Solid 3He–4He Mixtures Based on the Diffusion Mechanism

2007 ◽  
Vol 148 (5-6) ◽  
pp. 713-718
Author(s):  
V. N. Grigor’ev ◽  
I. A. Degtyaryov ◽  
S. S. Sokolov
Keyword(s):  
Phase Separation ◽  
Diffusion Mechanism ◽  
Solid 3He

Phase Separation During Film Deposition

1990 ◽  
Vol 202 ◽  
Author(s):  
M. Atzmon ◽  
C. D. Adams ◽  
Y.-T. Cheng ◽  
D. J. Srolovitz
Keyword(s):  
Phase Separation ◽  
Surface Morphology ◽  
Film Thickness ◽  
Diffusion Process ◽  
Solid Solutions ◽  
Diffusion Mechanism ◽  
Film Deposition ◽  
Terminal Phase ◽  
Interfacial Energies ◽  
Lateral Phase Separation

ABSTRACTWe report a study of the microstructure and surface morphology of co-deposited Al-Ge films. At 200 °C and above, the terminal solid solutions are obtained, whereas at lower temperatures, metastable amorphous or crystalline phases coexist with the Al-rich terminal phase. For film thickness below 200 nm, lateral phase separation is observed with surface grooving which reflects the bulk microstructure. Analysis of the data with a model for the diffusion process shows that the results are consistent with a surface diffusion mechanism. For thicker films, there is a transition into a layered microstructure in which Al segregates to the surface. This transition is explained in terms of the surface and interfacial energies of the phases.

The Role of the Diffusion Mechanism in Models of the Evolution of Microstructure During Phase Separation

1998 ◽  
Vol 529 ◽  
Author(s):  
T.T. Rautialnen ◽  
A.P. Sutton
Keyword(s):  
Monte Carlo ◽  
Phase Separation ◽  
Field Model ◽  
Diffusion Mechanism ◽  
Monte Carlo Model ◽  
Mean Field ◽  
Energy Functional ◽  
Square Lattice ◽  
Mean Field Model ◽  
Evolution Of Microstructure

AbstractWe have studied phase separation and subsequent coarsening of the microstructure in a two-dimensional square lattice using a stochastic Monte Carlo model and a deterministic mean field model. The differences and similarities between these approaches are discussed. We have found that a realistic diffusion mechanism through a vacancy motion in Monte Carlo simulations is cruicial in producing different coarsening mechanisms over a range of temperatures. This cannot be captured by the mean field model, in which the transformation is governed by the minimization of a free energy functional.

Atomic Diffusion of Al and Si in Cu44.25Ag14.75Zr36Ti5 Bulk Metallic Glass

2012 ◽  
Vol 510 ◽  
pp. 804-807
Author(s):  
Wei Yuan Yu ◽  
You Liang Wang ◽  
Wen Jiang Lu
Keyword(s):  
Diffusion Coefficient ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Diffusion Mechanism ◽  
Base Material ◽  
Atomic Diffusion ◽  
Diffusion Activation Energy ◽  
Metal Atoms ◽  
Secondary Ion ◽  
Diffusion Activation

Secondary ion mass spectroscopy (SIMS) has been adopted to study the diffusion of Al and Si in Cu44.25Ag14.75Zr36Ti5bulk metallic glass (BMG). It has been found that around the transition temperature of metallic glass, the relation between its diffusion coefficient and the temperature satisfy the same Arrhenius relation, which means the metallic transition has not caused change to the diffusion mechanism. In addition, the radius of Al atom is close to that of Si atom, but under the same temperature and time condition, the diffusion coefficient of Si atom in bulk metallic glass (BMG) is twice that of the Al atom, while there is not a big difference in diffusion activation energy. This is because as non-metallic element, the radius of Si atom has a strong binding force with the metal atoms in the base material, which also has a bigger diffusion coefficient.

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